Note that engineering majors had different admissions indices for SJSU, as noted on that page.
CS and other non-engineering majors were just GPA * 800 (+200 for frosh applicants graduating high school in Santa Clara County). The CS threshold of 3400 means a 4.25 GPA, or 4.00 GPA for a local applicant.
Note that GPA is recalculated from 10th-11th grade academic a-g courses, with up to 8 semesters of +1 honors points (“weighted capped”). See GPA Calculator for the University of California – RogerHub .
Engineering majors added +400 * math_GPA to the base admissions index score, which is why their thresholds appear higher.
Of course, changing into CS at SJSU after enrolling in another major is different: https://www.sjsu.edu/cs/advising/undergrad-advising/major-change.php